How many are democrats? How many are in a catholic school just because public schools are a disaster? It may well be that the leftist minded children are the products of pressure from not catholic sources.
It's true that the public schools in this particular city are disasters. The school accepts Catholic girls, Protestant girls, Islamic girls, etc., etc.(The city has a very large Islamic population -- I don't think being a Democrat has much to do with anything).
The school is open to anyone who wishes to apply and can do the work. The school requests that the girls follow their various religions and participate in church services or services at their Mosques.
You can't force teenagers to accept or not accept a certain way of life just because a teacher gets up in front of a class and gives the Church's opinion. Sometimes kids are contrary just to be contrary -- just to get a rise out of adults. Okay, that's fine. I did the same thing.
But I'll bet you five or ten years down the road (or even the day after graduation) when they marry and have children, they'll think twice about whether they approve of homosexual marriage or the lifestyle. They'll think twice because they will remember that they were taught something very different than what kids in many public schools are taught.
That's the difference.